Surface covering intended to be used on marking coverings for roads, parking areas and the like

ABSTRACT

Surface coverings for marking road surfaces are disclosed including elastic particles for application to the road surface, the elastic particles including a plurality of light reflectors such as glass beads or ceramic particles, which can also include various pigments.

BACKGROUND OF THE INVENTION

The present invention relates to a surface covering that is intended tobe used on marking coverings for roads, parking areas and the like, andwhich is designed to give optical directions. To give opticaldirections, the marking must be visible to the road-users, especiallydrivers of motor vehicles, and give directions as to how to drive, cycleor walk, or where to park their vehicles.

Road markings of this kind are used in every country where there is asufficiently high level of traffic, especially vehicular traffic, andwhere the roads have a solid surface, such as those made of asphalt orconcrete. These road markings can have different colors, but aregenerally white.

Road markings are generally made with thermoplastic materials or similarmaterials, which are laid on the roadway in the molten state. Themarking material is mainly a paint, which can be either water-based orsolvent-based. However, multi-component systems, often called coldplastics, are also used. In addition, the marking material can beprovided in the form of tapes. These tapes are supplied as “ready-mademarkings” and are fixed to the roadway with the aid of an adhesive layerapplied to their underside. The markings can be in the form ofcontinuous lines running along the edge of the road; parallel transversestripes; continuous or other lines in the middle of the roadway, orarrows indicating the driving direction. Parking areas are alsogenerally provided with such markings. Besides a binder, the markingmaterials often comprise fillers and light-reflecting beads that makethe markings readily visible when light is shone on them in the dark.

These road marking materials can have very different structures andchemical compositions. Examples of such road marking materials aredescribed in U.S. Pat. No. 3,253,146 and British Patent No. 2,043,673.All of the known markings in use are wear-resistant to a certain extent,and after being applied, they can withstand the load to which they aresubjected e.g. by the wheels of vehicles.

In the case of flat road markings, the light-reflecting glass beads liebelow the surface for the greater part of their size. In dry weather,the light beam of a car impinges on the upper part of these glass beads,and the light is reflected back from the rear inside surface of thebeads, so that the beads and the road marking can be easily seen. Indamp weather or rain, however, a film or layer of water is formed onthese beads, as a result of which the light is not reflected back, butis deflected in the direction of the light beam. In such a case, theroad marking cannot be readily seen, and its efficiency in the dark indifficult conditions may be reduced by 80 to 90% in comparison with itsefficiency under dry conditions. It is therefore desirable to somehowraise the glass beads above the surface, so that they lie above thelayer of water. However, the problem with this solution is that thebeads are then subject to excessive wear and tear, caused especially bystudded tires, while snowplows—where used—can simply shave theprojecting beads off. The situation is the same with the transversestripes, where the road markings between the stripes are completelyinvisible in damp weather. If the beads are arranged on a firm base, andproject up between these stripes, they are again quickly worn off by thewheels of vehicles, especially if these are fitted with studs, and theyare also shaved off by snowplows.

SUMMARY OF THE INVENTION

In accordance with the present invention, these and other objects havenow been realized by the invention of surface coverings for use inmarking a road surface comprising elastic particles for application tothe road surface, the elastic particles including a plurality of lightreflecting members including glass beads and/or ceramic particles. In apreferred embodiment, the elastic particles include pigments. Preferablythe pigments include pigments such as fluorescent pigments,phosphorescent pigments and/or color pigments.

In accordance with one embodiment of the surface coverings of thepresent invention, the elastic particles comprise an elastic materialsuch as elastomers or thermoplastic elastomers. In a preferredembodiment, the elastomers include natural rubber, styrene rubber,chloroprene rubber, ethylene propylene diene monomer rubber, nitrilerubber, fluorocarbon rubber, silicone rubber and/or polyurethane rubber.

In accordance with another embodiment of the surface coverings of thepresent invention, the thermoplastic elastomers include styrene isoprenestyrene rubber, styrene butadiene styrene rubber, ethylene vinyl acetatecopolymer, thermoplastic olefins, thermoplastic urethanes, polyesters,polyethers, and/or polyamides.

In accordance with another embodiment of the surface coverings of thepresent invention, the surface covering comprises a monolayer of theelastic particles.

In accordance with another embodiment of the surface coverings of thepresent invention, the surface covering comprises multiple layers of theelastic particles.

In accordance with another embodiment of the surface coverings of thepresent invention, the elastic particles have a shape such a spherical,conical, rod-shaped, rhomboidal or cubic shapes.

In accordance with a preferred embodiment of the surface coverings ofthe present invention, the elastic particles have a size of between 0.5mm and 20 mm.

The need to solve the above problems have long been felt, and the aim ofthe present invention is therefore to provide a surface covering whichis intended to be used on marking coverings for roads, parking areas andthe like, characterized in that it consists of elastic particlescomprising light-reflecting glass beads or ceramics.

The surface covering according to the present invention suitablycomprises one or more pigments, possibly including fluorescent and/orphosphorescent ones, and pigments that confer color and covering abilityon it.

Besides the glass beads or ceramics, the particles according to thepresent invention suitably consist mainly of elastomers, such as naturalrubber, styrene rubber, chloroprene rubber, ethylene propylene dienemonomer (EPDM) rubber, nitrile rubber, fluorocarbon rubber, siliconerubber or polyurethane rubber, or of thermoplastic elastomers, such asstyrene-isoprene-styrene (SIS) rubber, styrene butadiene-styrene (SBS)rubber, ethylene-vinyl acetate copolymer (EVA), thermoplastic olefins,thermoplastic urethanes, polyesters, polyethers, polyamides, and/ormixtures of these.

Furthermore, the surface covering according to the present inventionsuitably consists of particles forming a single particle layer(monolayer).

The particles according to the present invention are suitably spherical,conical, rod-shaped, rhomboidal or cubic in shape.

The particles according to the present invention should have a size ofbetween 0.5 mm and 20 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described below in more detail with referenceto the following detailed description, which in turn refers the attacheddrawings, where

FIG. 1 is a side, elevational diagrammatic representation of threedifferent embodiments of the elastic particles according to the presentinvention

FIG. 2 is a side, elevational diagrammatic representation showing howthe light is reflected and deflected by a road marking of the known typein dry and wet weather, and how the light is reflected by a road markingin the case of a surface covering according to the present invention indry and wet weather, and

FIG. 3 is a side, elevational view of the elastic particles of thepresent invention applied between transverse stripes on a roadway, inthe unloaded and the loaded state.

DETAILED DESCRIPTION

FIG. 1 shows a cross section of three embodiments of the elasticparticles according to the present invention. The particle on the leftin FIG. 1 is approximately spherical, that in the middle is rod-shaped,and the particle on the right is conical. The figure is onlydiagrammatic, and other embodiments are also possible.

As can be seen from FIG. 1, the particles are composed of a large numberof beads 1, which are embedded in an elastic binder. This binderconsists of some type of elastomer, such as natural rubber, styrenerubber, chloroprene rubber, ethylene propylene diene monomer (EPDM)rubber, nitrile rubber, fluorocarbon rubber, silicone rubber orpolyurethane rubber, or of thermoplastic elastomers, such as styrene-isoprene-styrene (SIS) rubber, styrene-butadiene-styrene (SBS) rubber,ethylene vinyl acetate (EVA) copolymer, thermoplastic olefins,thermoplastic urethanes, polyesters, polyethers, polyamides, and/ormixtures of these. The particles illustrated in FIG. 1 comprise glassbeads throughout their mass, but it is also possible to apply the glassbeads only to their surface. In the embodiments illustrated, the glassbeads are placed in a mold, and the elastomer mass is poured over themand then vulcanized. However, other manufacturing processes can also beused, in which the rubber mass is first shaped, and the glass beads arethen applied to its surface later. It is important to ensure, however,that the glass beads do not lie too close to one another, otherwise theyrisk being crushed during deformation of the particle.

FIG. 2 shows four cases, of which the upper two refer to abead-containing covering according to the prior art, while the lower tworefer to coverings with the elastic particles according to the presentinvention.

In the upper two drawings, the glass beads 1 are applied to the surfaceof a road marking 2 according to the prior art. A beam of light 3,coming e.g. from the headlights of a car, impinges on the glass beads atan acute angle and is reflected back to the driver as a light beam 4,travelling along almost the same path as the beam 3, but in the oppositedirection. The lower of these top two drawings shows the case when thebeads 1 are covered by a layer of water 5. The beam 3 from theheadlights is now deflected to form a beam 6 that is not reflected backto the driver. This means that the driver does not see this beam, and sothe visibility of the road marking is greatly reduced.

The upper of the two lower drawings shows how the light is reflectedwhen the particles according to the present invention are used on theroad marking 2. The particles, which can have a height of from about 0.5to 20 mm and comprise glass beads 1 either on their surface ordistributed throughout their mass, are hit very favorably by the lightbeam 3, which is reflected back as a light beam 4. This part of thefigure shows the situation in dry weather, while the lower drawing showsthe case when there is a layer of water 5 lying on the marking 2. Inthis case, the beads 1 project above the layer of water 5 and thereforereflect the light 3 back as a beam 4 in the same way as in the previouscase when the road is dry.

FIG. 3 shows how the particles are applied to a road marking 2 thatcomprises transverse stripes 7. The elastic particles according to thepresent invention project somewhat above the stripes 7, and the markingis therefore very clearly seen.

The lower part of FIG. 3 shows how the elastic particles are pressedtogether under loading, exerted e.g. by the wheel 8 of a car. The secondparticle from the left is depressed, while the first particle from theright, which was depressed before, has returned to its original state.In this way, the visibility of the marking is preserved, and the markingis not abraded in the same way as a hard, brittle marking. Even if e.g.a snowplow is driven over the covering, the particles according to thepresent invention yield and are pressed down, after which they riseagain instead of being shaved off.

In addition to the glass beads that are embedded in or applied to theelastic material, the elastic particles can also comprise a pigment,which confers color and covering ability on them. The use of a pigmentis part of the prior art and is often necessary if the glass beads orceramics are to reflect light to a sufficient extent. Pigments alsoimprove the visibility in daylight. Fluorescent and/or phosphorescentpigments can also be used, but they are expensive, and—if employed inthe customary road marking materials—they must be admixed to the wholematerial, which means that a large amount of such a pigment is needed.According to the present invention, on the other hand, it is possible toadmix the pigment only with the elastic particles, so that less pigmentis needed, and surface coverings having these properties are thereforemore economic. If required, friction compounds can also be added to thematerial.

The elastic particles according to the present invention have beendescribed here as a surface layer on conventional road markings. Singleparticle layers (monolayers) can be used, but there can also be a numberof layers, or the particles can be spaced out more than they are whenforming a continuous layer. It is also possible to lay these particlesdirectly on the roadway without any marking layer. A binder of some kindcan then act as a covering layer or the elastic particles can be pressedinto an unsolidified binding asphalt layer. It is also possible to laythe particles down in the form of various patterns, which can be donefor example with the aid of special machines. To make the particlesadhere to the surface of a customary road marking, they are applied tothe latter before the road marking or the binder has set, or they arebound to a dry road marking with the aid of a primer or adhesive.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

What is claimed is:
 1. Surface coverings for use in marking a roadsurface comprising elastic particles for application to said roadsurface, said elastic particles including a plurality of lightreflecting members selected from the group consisting of glass beads andceramic particles, wherein said elastic particles have a size of between0.5 mm and 20 mm.
 2. The surface covering of claim 1 wherein saidelastic particles include pigments.
 3. The surface covering of claim 2wherein said pigments are selected from the group consisting offluorescent pigments, phosphorescent pigments, and colored pigments. 4.The surface covering of claim 1 wherein said elastic particles comprisean elastic material selected from the group consisting of elastomers andthermoplastic elastomers.
 5. The surface covering of claim 4 whereinsaid elastomers are selected from the group consisting of naturalrubber, styrene rubber, choloroprene rubber, ethylene propylene dienemonomer rubber, nitrile rubber, fluorocarbon rubber, silicone rubber,and polyurethane rubber.
 6. The surface covering of claim 4 wherein saidthermoplastic elastomers are selected from the group consisting ofstyrene-isoprene-styrene rubber, styrene-butadiene-styrene rubber,ethylene vinyl acetate copolymer, thermoplastic olefins, thermoplasticurethanes, polyesters, polyethers, polyamides, and mixtures thereof. 7.The surface covering of claim 1 comprising a monolayer of said elasticparticles.
 8. The surface covering of claim 1 comprising multiple layersof said elastic particles.
 9. The surface covering of claim 1 whereinsaid elastic particles have a shape selected from the group consistingof spherical, conical, rod-shaped, rhomboidal, and cubic shapes.